Shane Holborn

Will Pearce

Erosion and Sediment Control Demonstration Facility

IntroductionErosion & Sediment Control Demonstration Facility

(TU10025)

Funded by the turf levy through Horticulture Australia Ltd (HAL)

Started under Queensland Government management at Redlands Research Station

Transferred to BioScience Australia Pty Ltd as a result of DAFF disinvestment in turf

Scheduled to run until February 2014 under this round of funding

Built a facilityRun monthly demonstration workshops for:

building, road construction and mining industries (practitioners); decision makers in local, state and federal government (specifiers);Partnering with training companies e.g. Absorb Enviro and Lend Lease.

Erosion and Sediment Control Demonstration Facility

Meet with practitionersIdentify barriers to useAddress barriers with research and by working with industry and decision

makers.

Erosion and Sediment Control Demonstration Facility

Erosion and Sediment Control Demonstration Facility

Extension of previous research with Dr Rob Loch - Optimising Turf Use to Minimise Soil Erosion on Construction Sites

Optimising Turf Use to Minimise Soil Erosion on Construction SitesFour main areas:

Study of hydraulic roughness of different turf types;Measurement of sediment trapping;Assessment of potential tunnelling under turf strips of various ages;Assessment of rates of root development in turf and impact of season on initial

root development.

ResultsHydraulic roughness of different turf types? (Hydraulic

roughness is the measure of the amount of frictional resistance water experiences when passing over land features). Showed increasing Manning’s n values as turf height

increased (i.e. decreased velocity)Sediment trapping capacity?

Turf was highly effective in trapping particles >0.05mm and able to cause some reduction in the 0.02 – 0.05mm range.

Turf will trap sediment sizes capable of moving through some silt fences/barriers.

Results - Sediment trapping

0 2 4 6 8 10 12 14Tim e (m in)

0

2

4

6

8

10

Tot

al S

edim

ent (

g/L)

In le tO u tle t

Tunnelling?

• Tunnel erosion potential and undermining of turf was not present and was able to handle large flows within 8 days

Root development differences and seasonal impacts?

• Little observable difference between species in summer but green couch, kikuyu and to lesser extent blue couch, faster to establish in winter

Results

1. A role for turf to control erosion by firstly reducing detachment

Erosion control

• turf on slopes up to 33% gradient; turfgrass seed could be promoted for steeper slopes.

• in channels with flow velocities >1.5 m/s;

Recommendations/specifications:

2. And trapping sediment

Sediment control•turf can enhance or replace sediment fences;

•preferred strip width of 2 m

•varying species depending on season is an option.

Could be considered as an option

Could be better option - functionality

Could be better option – safety and aesthetics

Works well in conjunction with other measures

Erosion demonstration facility

•Six bays in total, bays are 3mx10m (30m2)

•Water runs on sheet flow

•2L /sec

•8% slope

•To the outfall trough

•Water is timed running across the plot

•Samples are collected at 1 min intervals

•Turbidity measures taken to illustrate differences

Erosion demonstration bays

Erosion channel (video then 10:45)

•Demonstrate sediment movement and deposition in faster flows

•90 meters long

•500mm deep

•10-15 L/sec

•Snakes down the slope starting with a 1% slope along the top, coming round a bend at 3-4% slope and running down the hill at 8% toward the end

Information packs

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Erosion and Sediment Control